by Ashleigh Feltham,  Accredited Practising Dietitian and Accredited Nutritionist

Do you find it a challenge to fall and stay asleep?The number of people suffering from insomnia and sleep problems is growing worldwide. There are many factors that can affect your sleep quality, and one that may surprise is the health of your gut microbiome.

Your gut microbiome is as unique to you as your fingerprint and everyone’s optimal microbiome balance is slightly different. Saying this, there are key lifestyle factors that influence the health-promoting microbes, which support the health of your body and its functioning. This includes consuming a variety of different plant-based foods each day. Foods such as wholegrains, nuts, seeds, legumes, beans, vegetables and fruit.

Each of these different types of foods feed the health-promoting microbes in your gut. They provide different fuel sources, such as prebiotic fibre and polyphenols. Prebiotic fibre is a type of non-digestible carbohydrate that fuels the microbes in your gut. Give your gut some love with 30 different plant-based foods each week. In addition to eating a diet made up of predominantly plant-based foods, include with added inulin, which is a prebiotic and soluble fibre.

When your microbes feed on good fuel sources, they create messages, such as short chain fatty acids, neurotransmitters and secondary bile acids. These all have an effect on the functioning and health of your body via metabolites and compounds. Sleep promoting hormones such as melatonin and gamma-aminobutyric acid impact sleep. Also, compounds and metabolites that help to keep you awake and alert, such as cortisol, epinephrine, dopamine, orexin, serotonin, histamine and acetylcholine.

There is a negative impact on the quality of messages the gut microbiome sends out if your gut microbiome is in a suboptimal state. A diet high in red meat and ultra-processed foods, stress and certain medications disrupt the healthy balance of your gut. Research now provides new insight into the potential bidirectional link between sleep quality and gut microbiome health.

One review investigated this link. As sleep deprivation leads to disfunction of your gut microbiome, a suboptimal gut microbiome can lead to sleep disorders. This provided further insight into the potential role of your gut microbiome in getting a good night’s sleep.

Another review evaluated the potential of prebiotic, postbiotic and probiotics to improve sleep quality as well as reduce stress and anxiety. Probiotics can be defined as ‘live microorganisms, which when administered in adequate amounts confer a health benefit on the host.’ Postbiotics are the metabolites that probiotics produce after they consume prebiotic fuel. The review concluded that although more research is needed, there is some evidence that prebiotics, postbiotics and probiotics like bifidobacterial and lactobacilli may improve sleep quality and reduce stress.

An additional study investigated the effects of the types of gut microbes present in men who ate meals late at night, which is known to affect sleep quality. This cross-sectional pilot study used demographic information, questionnaires and a stool sample to determine the types of gut microbes present. Erysipelotrichales phyla were found to be at significantly higher levels in the men who ate meals late at night. More research is needed, but there may be links to the types of microbes present and sleep quality as well as the risk of health conditions such as metabolic diseases.

Take home message:

There are many lifestyle strategies that can help to set you up for a good night’s sleep. A strategy to try is including lifestyle choices to support an optimal gut microbiome.

References:

1. Mohammadi Z, Bishehsari F, Masoudi S, Hekmatdoost A, Stewart DA, Eghtesad S, Sharafkhah M, Poustchi H, Merat S. Association between Sleeping Patterns and Mealtime with Gut Microbiome: A Pilot Study. Arch Iran Med. 2022 May 1;25(5):279-284. doi: 10.34172/aim.2022.46. PMID: 35943002.
2. Haarhuis JE, Kardinaal A, Kortman GAM. Probiotics, prebiotics and postbiotics for better sleep quality: a narrative review. Benef Microbes. 2022 Aug 3;13(3):169-182. doi: 10.3920/BM2021.0122. Epub 2022 Jul 11. PMID: 35815493.
3. Hill, C., Guarner, F., Reid, G. et al. The International Scientific Association for Probiotics and Prebiotics consensus statement on the scope and appropriate use of the term probiotic. Nat Rev Gastroenterol Hepatol 11, 506–514 (2014).
4. The microbiota-gut-brain axis in sleep disorders. ZheWang et al. Sleep Medicine Reviews. Science Direct. Available online 31 August 2022.